Apparatus for punching holes in the closed ends of drawn-metal cylinders and the like



G. RABOLD SR APPARATUS FOR PUNCHING HOLES I N THE CLOSED RS AND THE LIKE Feb. 11, 19302 ENDS 0F DRAWN METAL CYLLNDE Original Filed. Nby.

n g M l "1- .2 on N T mm. Y B an mm o E VA Patented Feb. 11, 1930 UNITED sures PATENT OFFICE TUBE COMPANY, A CORPORATION AIPIEARATUS FOR BUNCHING HOLES IN THE CLOSED ENDS OF NEW JERSEY F DRAWN -METAL CYLINDERS AND THE LIKE Application filed November 2,1926, Serial No. mates. Renewed October as, 1929.

Seamless metal cylinders are usually drawn from ingots which havebeen pierced in a press for mounting on a mandrel and the front ends of said cylinders are closed. WVhen the cylinders are to be worked up, as for instance,to be out into annular sections such as are used for forming pipe couplers, a hole in the center of the closed end 1s requlred to mount the cylinder in the lathe or other cuttln or working mechanism.

it present the common practice tofirst remove the cylinder from the drawbench and then by a second operation, forming the hole in the end thereof as by the use of an acetylene torch. The objections to this practice are,

inter alia, the labor,material andequipment cost, and the tendency towards inaccuracyin the positioning and size of the hole.

In my improved apparatus the hole is punched while the cylinder is still in the draw bench and-as the drawingoperation is completed, and by one and thesame operation with the drawing of the cylinder, so that when the cylinder is removed from the draw bench its closed end is providedwith the neoessaryhole. y if y j I accomplish this purpose by mounting on the front end of the draw bench a properly centered punching mea'nsagainst which the closed end of the cylinder is forced by the movement of the drawing mandrehr thus punching out a core of the material ofthe desired diameter. The punchlng means 1smovable so that it may be shifted out of the way to permit theremoval of the drawn and punched cylinder from the draw table and mandrel.

The punching means is also adjustable to accommodate cylinders of different diameters end of the power cylinder.

and to produce holes of different diameters.

I also provide novel means for preventing the fracture of the mandrel or mandrel stem during the cutting operation and also fracture by the impact of the piston against the Other novel features of construction and also of arrangement of parts will appear from the following description.

Inthe accompanying drawings, wherein I have illustrated the best embodiment of the principles of my invention now known to me, Fig. 11s a broken longitudinal section of a draw table to which my improved punching means has been applied, the hole having just 55 showing the connection front elevation of the adjustable centering guide for the punch.

Referring to the drawings, 1 represents one of the supports of the draw bench which is indicated in part by the die carrier supports 2, the die carriers 3 and the dies 4.

. 5 represents the mandrel interchangeably mounted on the mandrel stem 5 whichis connected to the piston rod 6. The piston rodis connected to the piston 7 which works in the pressure cylinder 8, said cylinder being attached in the usual manner to the rear end of the draw bench.

At the front end the vided with a frame work which may be draw bench is promountedon the support 1 and whichincludes a pair of spaced apart brackets, one of which is shown at 9 in Fig. 1,.and which brackets are provided with opposed and vertically dis; posed slideways. 10 in which is. slidably mounted a head block 11 which may be lowered intoposition or raised therefrom by any convenient means, as by a chain hooked in the eye-bolt 12 which is screwed into the block11. m

The block 11 is supported in its lowered position by any convenient means. Thus I show a pair of horizontally and transversely disposed bars 1.3 and 14, the inner bar 13 being provided with a ledge 15 upon which the block 11 rests to properly position it in its lowered position. The bars 13 and 14: are shown supported by bolts 16 extending through holes in the bars and screwed into threaded holes 17 in the support 1. Surrounding the bolts 16 are the sleeves 18 which are interposed between the inner bar 13 and the support 1 to properly position the bar 13.

19 arenuts screwed on the outer end of the bolt16 to hold the bar 14 in position.

20 represents a circular abutment block which is fixed to the inner face of the head the rear of the block 11.

block 11 in proper position to be axially alined with the mandrel 5 when the block 11 is lowered into place. The preferred manner of securing the abutment block to the head block 11 is shown in Fi 1. Thus the abutment block 20 is provided with an axial hole 21 whose rear or outer end is threaded to receive the inner threaded end of a bolt 22 which is provided with an annular shoulder 23 abutting against the rear face of the block 20. The head block 11 is provided with a hole 24 through which the bolt 22 extends. The outer end of the bolt 22 protrudes through the block 11 and is threaded to receive a nut 25 which is screwed up against Thus the abutment block is mounted rigidly but removably on the front face of the block 11. The front end of the hole 21 in the block 20 is countersunk, forming the internal shoulder 26, and 27 is the cylindrical shear block which is seated in said hole and bears against said shoulder 26, said shear block protruding from the abutment block.

28 is an annular cushion plate mounted on the face of the block 20 and surrounding the shear block 27. The plate 28 is resiliently mounted on the block 20 as by means of pins 29 extending from the back of plate .28 into socket holes 30 .in the block 20. These holes are countersunk to receive the helical springs 31 coiled about the bolts and bearing outwardly on the plate 28. The plate 28 thus cushions the blow of the mandrel on the abutment block when the punching operation is efiected.

32 represents the centering ring which fits around the abutment block 20 and which is interchangeable to provide for various external diameters.

v 33 represents the segmental guides which co-act to receive and properly center the cylinder in relation to the shear block. The segments 33 unite to form an interrupted annular guide to receive the cylinder.

The segments are best illustrated in Fig. 3 and are of the following construction. 34 are the Hat bases which fit against the inner face of the head block 11 and are detachably clamped thereto by the bolts 35 which extend through slotted holes 36 in the bases 34 and are tightened in threaded holes 37 in the block 11. The holes are slotted so that the segments 33 may be adjusted toward or away from a common center.

Each segment has an arcuate flange 38 rising from its base 34 and described on a radius from the common center of the guide and at each end of the flange 38 is an outwardly extending wing flange 39 disposed on a line radial of said common center. The wing flanges 39 are pierced with holes for the clamping bolts 40 which secure the segments together. 42 represents buttress flanges for the flanges 38.

in the mandrel.

For different diameters of cylinders spacer rings 32 of different thicknesses are provided, the segments 33 being clamped snugly about the spacer rings to constitute the guide, and the internal diameter or capacity of the guide being determined by the external diam eter of the spacer used. The shear block 27 is removably held in its seat in the abutment block 20 as by a long bolt 43 whose front end is screwed into a threaded hole in the rear of the shear block and which extends through an axial hole in the larger bolt 22. The protruding outer end of the bolt 43 is provided with a nut 44 which is screwed, against the outer end of the bolt 22. The shear block protrudes from the cushion plate 28 to a degree at least sufiicient to enable it to punch the hole in the end of the cylinder.

The method of operation is as follows:

A spacer ring 32 of the proper exterior diameter is slipped in place about the abutment block 20 and the guide segments 33 are adjusted about the spacer ring to produce the proper internal diameter to receive the end of the drawn cylinder. The head block 11 is then lowered into proper position.

The drawing operation is then proceeded With and the cylindrical shape is pushed through the last die 4 and forced against the abutment block 20, the protruding shear block 27 punching out a cylindrical core 45 from the center of the head 46 of the drawn cylinder 47 as shown in Fig. 1.

The front end of the mandrel 5 is axially recessed as at 48 to give clearance for and receive the displaced core 45.

The mandrel and cylinder are then backed off to clear the shear block 27 from the end of the cylinder and also to clear the cylinder from the segmentalguides 33 and the head block 11 and its associated parts are raised to permit the cylinder to be stripped from the mandrel.

To enable the mandrel to discharge the core 45 I provide the mandrel with a plunger 49 working in the recess 48 and carried by a stem 50 which extends through an axial bore 51 The stem 50 is resiliently pressed forwardly by a spring 52 which occupies the enlarged rear end of the bore and bears against the double-ended coupling stud 53 which connects the mandrel to the mandrel stem. The rear end of the stem 50 is provided with an enlarged head to limit the outward movement of the plunger 49.

Thus as soon as the shear block 27 is released from the hole in the end of the cylinder the plunger 49 ejects the core 45. When the core 45 is punched and displaced from the end of the cylinder the tendency is for the mandrel to jump forwardly because of the relief of the resistance to its movement and this tends to cause a breakage at the weakest point in the mandrel, which is usually the double-ended stud 53 connecting the mandrel t0 the mandrel stem or at the swinging head connection 54, Fig. 2, which connects the mandrel stem 5? with the piston rod 6.

To avoid such a fracture I provide a slip joint in the mandrel stem 5, shown in Fig. 2. Thus the mandrel stem 5 is made separate from its rear end portion 5 and the latter is provided with a threaded aXial borein which is screwed the threaded shank of a stud 55 whose circumferentially enlarged head 56 works in a bore in the end of the mandrel stem 5 and is prevented from pulling out of the same by the eXteriorly threaded bushing 57 which screws into the outer threaded end of the bore. Thus when the mandrel tends to spring forwardly as the hole. is punched in the cylinder the mandrel stem will move forwardly independently of the piston rod and piston for a limited extent, thus avoiding fracture, the forward movement ofthe mandrel being cushioned by the plate 28.

In Fig. 2 I show at 58 the usual clamp connection'between the mandrel stemand the piston rod, and 59 represents the sliding cross head which guides the movement of the piston rod and mandrel stem.

Again I find that when the piston 7 en gages the front end of the cylinder 8 there is a jar which tends to strain and break away the piston rod from the piston.

I provide a slip joint between the piston and the piston rod, a headed stud 6Q screwed into the piston rod and working 1n a bore .61 in the piston and being prevented from disengagement therefrom by the reduced front end of the bore 61.

Thus when the piston strikes the end of the cylinder at the completion of a forward stroke the piston rod and mandrel are free to move forwardly a limited degree which distributes the effect of the jar over the whole operation.

It is evident from the foregoing that by the use of my apparatus the hole in the closed end of the drawn cylinder is punched in one and the same operation by which the cylinder is drawn.

It is also evident that the hole is cleanly cut and accurately positioned and sized.

that I desire to claim is 1. The combination of a draw-table, a series of drawing dies mounted on said table, a movable mandrel having travel through said dies to draw a cylinder mounted 011 said mandrel, and a hole punching means lnterposed in the path of the end of the cylinder as it travels with said mandrel for the purpose de scribed.

2. The combinatlon of a draw-table, a se ries of drawing dies mounted on said table, a

movable mandrel having travel through said dies to draw a cylinder mounted on said mandrel, and a punch positioned at the delivery end of the table and interposed in the path of of drawing the table and interposed in the path of the closed end of the cylinder as it travels with the mandrel along said table, and means for moving said punch into and out of the path of said cylinder. i

4. The combination of a draw-table, a series of drawing dies mounted on said table, a movablemandrel havingtravel through said dies to draw a cylinder mounted on said man drel, and a punch positioned at thedelivery end of the table and interposed in the path of the closed end of the cylinder as it travels with the mandrel along said table, the end of the mandrel being recessed to receive the core punched out of theend of the cylinder.

5. The combination of a draw-table, a series dies mounted on said table, a movable mandrel having travel through said dies to draw a cylinder mounted on-said mandrel, a punch positioned at'the delivery end of the table and interposed inthe path of the closed end of the cylinder as it travels with the mandrel along said table, the end of the punch being recessed to receive the core punched from the end of the cylinder, and means for ejecting the core from said recess.

6. The combination of a draw-table, a se ries of drawing dies mounted on said table, a movable mandrel having travel through said dies to draw a cylinder mounted on said mandrel, a punch positioned at the delivery end of the table and interposed inthe path of the closed end of the cylinder as it travels with the mandrel along said table, the end of the punch being recessed to receive the core punched from the end of the cylinder, and spring plunger means for ejecting the core from said recess.

7. The combination of a draw-table, a series of drawing dies mounted on said table, a movable mandrel having travel through said dies to draw a cylinder mounted on said mandrel, a punch positioned at the delivery end of the table and interposed in the pathof the closed end of the cylinder as it travels with the mandrel, and means for cushioning the movement of the mandrel as thepunch displaces a core of metal from the cylinder end.

8. The combination of a draw-table, a series of drawing dies mounted on said table, a movable mandrel having travel through said dies to draw a cylinder mounted on said mandrel, a punch positioned at the delivery end of the table and interposed in the path of the closed end of the cylinder as it travels with the mandrel and a cushioningabutment which the end of the cylinder engages as the punch displaces the core of metal from the cylinder end.

9. The combination of a draw-table, a series of drawing dies mounted on said table, 5 a movable mandrel having travel through i said dies to draw a cylinder mounted on said mandrel, a hole punching means in the path of the end of the cylinder as it travels with 7 said mandrel, power-actuated means opera- 1o tively connected to'the mandrel to cause the mandrel to travel, and a lost motion connection between the mandrel and said power. actuated means whereby the quick forward motion of the mandrel when the hole is punched 15 is prevented from causing fracture.

10. The combination of a draw-table, a series of drawing dies mounted on said table, a movable mandrel having travel through said dies to draw a cylinder mounted on said man- 1 go drel, a hole punching means in the path of the end of the cylinder as ittravels with said mandrel, power-actuated means operatively connected to the mandrel to cause the mandrel to travel, and means whereby the man- 35 drelmay have a limited travel independent of the power-actuating means when the hole is punched. V

Signed at McKeesport this 28th day of October, 1926. .30 GEORGE RABOLD, SR. 

